While it's good to get DOT approved lights, I've never had my tail lights inspected. Short of getting something that is just horribly and clearly wrong at a glance, I don't see it being an issue.
There are a lot of locations in the US where inspection is mandatory.
If inspection services operate your tail lights and can see the difference of lumens, you'll be getting a notice and replacing what you have.
LED tail lights have different diffusion characteristics than a filament bulb. I can usually spot a replacement LED/array and original lens from over 100' away.